N’Golo Kante did not play for Chelsea on Sunday in a 1-0 loss at Manchester City, and his absence was one of many factors that contributed to a woeful performance.

The performance, however, must have been unconcerning compared to what Kante’s Blues teammates witnessed Friday.

According to a report from the Telegraph, later confirmed by others, the French midfielder fainted at the club’s training ground two days before the City game. The report states that Chelsea players were “shocked” and “terrified Kante had suffered a heart problem when he momentarily passed out in front of them after training.”

Fortunately, subsequent tests determined Kante did not have a heart problem. From the Telegraph:

A Chelsea doctor arrived on the scene within seconds after Kante slumped to one side in the dressing room at the club’s Cobham training ground after Friday’s session.

Having regained consciousness and been attended to on site, Kante was sent to a specialist for a series of cardiology tests, which, fortunately, all came back clear.

Kante traveled with Chelsea to Manchester for the game against City, and was initially cleared to play, but reportedly felt unwell on the morning of the game. He was thus left out of the squad by manager Antonio Conte. Chelsea attributed his absence to illness.

The 26-year-old returned to training Monday on his own while other Chelsea players had the day off, and is expected to be available for Chelsea’s game against Crystal Palace on Saturday. The Blues then travel to Barcelona for their Champions League round of 16 second leg the following Wednesday.